Medeshamstede (/miːdsˈhæmstɛd/) was the name of Peterborough in the Anglo-Saxon period. It was the site of a monastery founded around the middle of the 7th century, which was an important feature in the kingdom of Mercia from the outset. Little is known of its founder and first abbot, Sexwulf, though he was himself an important figure, and later became bishop of Mercia. Medeshamstede soon acquired a string of daughter churches, and was a centre for an Anglo-Saxon sculptural style.

Nothing is known of Medeshamstede's history from the later 9th century, when it is reported in the Anglo-Saxon Chronicle of 864 to have been destroyed by Vikings and the Abbot and Monks murdered by them, until the later 10th century, when it was restored as a Benedictine abbey by Bishop Æthelwold of Winchester, during a period of monastic reform. Through aspects of this restoration, Medeshamstede soon came to be known as "Peterborough Abbey".

The name has been interpreted by a place-name authority as "homestead belonging to Mede".

An alternative description is 'Medu' meaning Mead then 'Hamme' a village on a river and 'Steð'(the ð is pronounced th) meaning a bank or sea shore(the sea was about 4.5 metres higher in early saxon times), so the 'Mead village in the valley with a landing stage'

According to the Peterborough version of the Anglo-Saxon Chronicle, written in the 12th century, this name was given at the time of the foundation of a monastery there in the 7th century, owing to the presence of a spring called "Medeswæl", meaning "Medes-well". However the name is commonly held to mean "homestead in the meadows", or similar, on an assumption that "Medes-" means "meadows".

The earliest reliable occurrence of the name is in Bede's Ecclesiastical History, where it is mentioned in the genitive Latinised form "Medeshamstedi", in a context dateable prior to the mid-670s. However the area had long been inhabited, for example at Flag Fen, a Bronze Age settlement a little to the east, and at the Roman town of Durobrivae, on the other side of the River Nene, and some five miles to the west. It is possible that "Medeshamstede" began as the name of an unrecorded, pre-existing Anglian settlement, at or near the site.

Another early form of this name is "Medyhæmstede", in an 8th-century Anglo-Saxon royal charter preserved at Rochester Cathedral. Also found is "Medelhamstede", in the late 10th century Ælfric of Eynsham’s account of the life of St Æthelwold of Winchester, and on a contemporary coin of King Æthelred II, where it is abbreviated to "MEĐEL" /ˈmiːðəl/. A much later development is the form "Medeshampstede", and similar variants, which presumably arose alongside similar changes, e.g. from Old English "[North] Hamtun" to the modern "Northampton". Despite the fact that they are therefore strictly unhistorical, forms such as "Medeshampstede" are found in later, historical writings.

Locally, Anglo-Saxon records use "Medeshamstede" up to about the reign of King Æthelred II, but modern historians generally use it only to the reign of his father King Edgar, and use "Peterborough Abbey" for the monastery thereafter, until it changes to "Peterborough Cathedral" in the reign of King Henry VIII.